The following gear blanks all have a pitch diameter of 10 Wings3d Units. To make a pair, for example a 61 tooth and
a 15 tooth. Circular pitch = Pitch Diameter*PI/61=0.515015. The 15 tooth gear has to have the same circular
pitch. 15*0.515015/PI=2.45902 this is the pitch diameter of the 15T gear. This
image shows the meshing of the two gears. To scale the 15T gear do a RMB radial scale in Wings3d using the centre vertex
at 24.5902%. There is no clearance built in to the models. If you need clearance you'll need to do it yourself.
If you're making a matching rack you'll need the addendum and dedendum. The addendum in this case and always (afaik) is the pitch diameter/number of teeth.
The dedendum for the gears below is 1.25*addendum.
Addendum = the tooth depth outside the pitch circle diameter.
Dedendum = the tooth depth inside the pitch circle diameter.
It might be necessary to do some further smoothing of the models depending on the intended use. I suggest
smoothing just the peripheral faces rather than smoothing the whole body as the front and back faces are flat.
If you need a gear with a higher tooth count I'll add it to the list. Use the contact form link at the head of this page
to request a special.
Untested but you can make helical gears with a bit of work. Divide the peripheral edges into a suitable number creating edge
loops. After working out the angle successively rotate each edge loop.